Siouxsie and the Banshees, Leeds Uni in 1978. They really shouldn't have been top of any bill at that stage, I think The Scream had literally just come out. Anyway she moaned throughout about how boring the crowd were, how she couldn't get anything from us, etc. etc. There was a brief pogo to Hong Kong Garden. There was no encore.
Wah! Heat in about 81, something like that. Pete Wylie was in full rock star mode and was swigging from a bottle of Jack Daniels throughout. I think he'd been drinking all day and he was ***ed and virtually incapable.
Last Autumn went to see Rosalie Cunningham at the Georgian. They turned up late. Very late. They kept the audience sweating in the bar while they endlessly sound checked. When they finally got on, they were making the set list up on the hoof, and it showed. Very disappointing.
Too many gigs spoilt by other audience members, but I guess that doesn't count.